Rollup merge of #51789 - estebank:issue-50577, r=oli-obk

Don't ICE when performing `lower_pattern_unadjusted` on a `TyError`

Fix #50577. CC #51696.

r? @oli-obk

src/test/ui/issue-50577.rs

@@ -0,0 +1,15 @@
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+fn main() {
+    enum Foo {
+        Drop = assert_eq!(1, 1)
+    }
+}

src/test/ui/issue-50577.stderr

@@ -0,0 +1,13 @@
+error[E0317]: if may be missing an else clause
+  --> $DIR/issue-50577.rs:13:16
+   |
+LL |         Drop = assert_eq!(1, 1)
+   |                ^^^^^^^^^^^^^^^^ expected (), found isize
+   |
+   = note: expected type `()`
+              found type `isize`
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0317`.